Crystalloid material in cells of the murine mononuclear phagocyte system.

In an attempt to throw further light on the nature and distribution of crystalloid material in macrophages, tissues from a variety of locations in 9 normal adult mice of 36-46 g body weight were studied by light and electron microscopy. Crystalloid inclusions were widely distributed in mononuclear phagocytic cells, being present in macrophages of the bone marrow, spleen, lung and ileum and in the Kupffer cells of the liver. They were not observed in the macrophages of the thymus, parotid lymph node or skin nor were they seen within the lymphatic nodules of Peyer's patches. The observed distribution of crystalloid material seems consistent with its suggested origin from granulocyte breakdown.